Thank you for the update. Now I understand better about the issue. Please try modifying the following registry key and then test it again:
Note: Serious problems might occur if you modify the registry incorrectly. For added protection,
back up the registry before you modify it.
1. Close Outlook.
2. Press Windows key + R to open the Run command, type regedit and press Enter to open the Registry Editor.
3. Navigate to the following registry key:
HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Options\Reminders
4. Delete the WindowsPos value from the right pane.
5. Restart Outlook.
Please let me know the result.
Regards,
Steve Fan
Forum Support